The present invention relates to a reciprocating mechanism, and more particularly to an engine, such as an internal combustion engine, including such a mechanism.
Known reciprocating mechanisms include crank mechanisms and cam mechanisms. Internal combustion engines exclusively use crank mechanisms to translate their linear motion of a piston sliding up and down in a barrel into rotation of an output shaft.
According to one aspect of the present invention, there is provided a reciprocating mechanism including a reciprocating member, movable in a substantially linear reciprocating direction between two ends of travel, a piston provided on the reciprocating member, and a constant breadth cam and follower, the follower being coupled directly to the reciprocating member to translate linear movement of the reciprocating member into rotary motion of the cam, and the mechanism being such that movement of the reciprocating member at the two ends of its travel is reversed in dependence upon the rotation of the said cam, wherein the follower lies below and to the side of the piston bore and the piston is rigidly mounted to the reciprocating member.
Preferably, the constant breadth cam and follower member are coupled to a pendulum counterbalance.
According to a second aspect of the present invention, there is provided an engine including the reciprocating mechanism of the first aspect of the invention.
A piston may be provided at each end of the reciprocating member.